Using data from the U.S. National Natality Survey (1980) this project will examine the effects of the birth's planning status, the utilization of prenatal care, and maternal smoking during pregnancy on birth weight. The basic hypothesis is that unplanned births weigh less than planned ones and the differences in prenatal care and smoking are instrumental in producing this relationship. A number of social and demographic variables are controlled. Comparisons are made between Hispanics, Blacks, and Anglos. Statistical techniques to be employed include OLS regression in a path analytic format (when birth weight is coded continuously), logit analysis (when birth weight is dichotomized as low/normal) and conditional logit analysis (when birth weight and gestational age are cross-classified to indicate infant maturity).